This relates to electronic devices and, more particularly, to electronic devices with displays.
Electronic devices such as cellular telephones and computers are often provided with displays. To ensure that displays are visible in a wide variety of lighting conditions, displays are often provided with backlight units. A light source such as an array of light-emitting diodes may provide a backlight unit with light. A transparent light guide plate may be used to laterally distribute light from the light-emitting diodes over the display.
To enhance backlight efficiency and thereby ensure that a display exhibits satisfactory backlight brightness levels, brightness enhancing films are often incorporated into a display backlight unit. These films, which are sometimes referred to as prism films or turning films, help direct light escaping from the light guide plate upwards through display layers towards a user.
If care is not taken, the layers in a display such as prism or turning film layers may be susceptible to damage. For example, conventional prism or turning film surface features may be crushed during an impact event, leading to undesirable dark and white spots on a display.
It would therefore be desirable to be able to provide improved display backlight structures.